Coeliac disease: to classify or not to classify – that is the question!

I have followed the discussion on the classification of coeliac disease (CD) published in the autumn issue of Gastroenterology and Hepatology from Bed to Bench with great interest. In my opinion, the ongoing debate on CD focuses around three issues: firstly, do we need a duodenal biopsy for the diagnosis of CD? Secondly, is it necessary to classify the mucosal pathology? Thirdly, which classification is the most reproducible and useful one for clinical assessment of the patient? Regarding the abovementioned issues, below, is the summary of my view, as a pathologist. We have reached the era where the duodenal biopsy is no longer the gold standard for the diagnosis of CD. We need new tools like mucosal tTG antibodies to diagnose cases sensitized to gluten with normal intestinal mucosa or " microscopic enteritis ". However, duodenal biopsy is still considered essential in the diagnostic work-up of adult CD and cannot totally be replaced by serology in many clinical settings. Since there is no correlation between degree of mucosal damage and severity of clinical symptoms in CD, classification of mucosal pathology may seem totally irrelevant from a clinical point of view. However, from a pathologist's point of view, intraepithelial lymphocytosis and flat mucosa are distinct forms (" grades ") of mucosal pathology and may be caused by a variety of entities besides CD. Therefore, the type and degree of mucosal pathology should be reported in a descriptive manner. If pathologists wish to classify the mucosal pathology, a standardized, reproducible, logical and preferably simple classification scheme is essential to avoid unnecessary confusion. The clinician should know the histopathologic appearance of the mucosa, to relate serology and other laboratory findings to the clinical picture and make a differential diagnosis,. Marsh, who is a gastroenterologist, has pioneered classifying CD after years of experimental and clinical research and defined the spectrum of mucosal pathology in CD (1). I believe, even Marsh did not expect his scheme to receive such a warm welcome from practising pathologists and become very popular in the evaluation of intestinal biopsies. However, it is interesting that subsequent modifications of the original Marsh classification were proposed by pathologists including Oberhuber (2), Corazza Villanacci (3), and Ensari (4). Unfortunately, Oberhuber's modification (2) did not gain much popularity among pathologists since it was based on subjective definitions such as " minor or moderate degrees of shortening and blunting of the villi " or " …